Gas generators are known which have an oblong housing in which a combustion chamber insert carrying a solid propellant is arranged. The fastening of the combustion chamber insert in the gas generator is to be brought about as simply and quickly as possible, for reasons of cost. At the same time, however, it must be ensured that the combustion chamber insert is held without play over the entire lifespan of the gas generator, in order for example to prevent a rattling.